Metabolism of bioactive agents (hereafter "drugs") to inactive or excretable derivatives is undesirable in many treatment regimes because it leads to a reduction in bioavailability. This may necessitate increasing dosage of the drug and this can lead to adverse side effects. The most significant enzymes responsible for such metabolism are the cytochrome P450 enzymes such as the CYP3A4 isozyme. Most agents known to inhibit CYP3A4 have significant adverse effects that make them unsuitable for co-administration with the drug.
The present invention aims to overcome these and other problems of the prior art.